The speed of light in a block of glass is found to be 1 . 90 × 10 8 ms - 1 . Calculate the refractive index of the glass. (The speed of light in a vacuum is 3 × 10 8 ms - 1 )

Given: The speed of light through glass = 1 . 90 × 10 8 ms - 1 , The speed of light in vacuum = 3 × 10 8 ms - 1 . The Refractive index is defined as the ratio of the speed of light in a vacuum or air to the speed of light in the medium. In terms of the formula we have, η = c v Where c is the speed of light in a vacuum, v is the speed of light in a medium. By substituting, η = 3 × 10 8 1 . 9 × 10 8 = 1 . 57 .

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Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.7

HARD

Upper Secondary: IGCSE

IMPORTANT

Earn 100

Draw a diagram to show how a ray of light passes through a parallel-sided block of glass or Perspex.

Important Questions on Light

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.1

Write the word AMBULANCE as it would appear when reflected in a plane mirror.

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.1

Why is it sometimes written in this way

on the front of the ambulance?

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.2

Draw a diagram to illustrate the law of reflection.

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.3

A ray of light strikes a flat, reflective surface such that its angle of incidence is

30 °

. What angle does the reflected ray make with the surface?

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.11

Look at the table. What is the value of the refractive index of a diamond?

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.13

Light travels more quickly through water than through glass. If a ray passes from glass into water, which way will it bend: towards or away from the normal?

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 13 - Light>Questions>Q 13.14

The speed of light in a block of glass is found to be